Coil component and method for manufacturing coil component

Abstract

A coil component includes a drum core including a winding core portion and flange portions on opposite sides of the winding core portion in its axial direction, a wire wound around the winding core portion, and a sheet core arranged on a top surface of each of the flange portions and on the wire with an adhesive interposed therebetween. The adhesive contains no filler. A shortest distance between the top surface of the flange portion and the sheet core is not smaller than about 3 μm.

What is claimed is: 
     
       1. A coil component comprising:
 a drum core including a winding core portion and flange portions on opposite sides of the winding core portion in an axial direction of the winding core portion; 
 a wire wound as a coil around the winding core portion; and 
 a sheet core arranged on a top surface of each of the flange portions and on the wire with an adhesive interposed therebetween which contacts the winding core portion, 
 wherein the adhesive contains no filler, 
 a shortest distance between the top surface of the flange portion and the sheet core is not smaller than about 3 μm, 
 opposite outer edges of an inner layer of the coil are spaced from inner surfaces of the flange portions which extend between the respective top surfaces and bottom surfaces of the flange portions, 
 a gap in the adhesive exists in areas between the opposite outer edges of the inner layer of the coil that contacts the winding core portion and the inner surfaces of the flange portions, 
 the adhesive extends continuously between opposite outer edges of a second layer of the coil that is on the inner layer of the coil and the inner surfaces of the flange portions, 
 a number of turns in the second layer of the coil is less than a number of turns in the inner layer of the coil, and 
 each turn in the second layer of the coil contacts two adjacent turns in the inner layer of the coil, and the opposite outer edges of the inner layer of the coil extend beyond the opposite outer edges of the second layer of the coil. 
 
     
     
       2. The coil component according to  claim 1 , wherein a shortest distance between the wire and the sheet core is smaller than about 50 μm. 
     
     
       3. The coil component according to  claim 2 , wherein the wire is wound around the winding core portion in multiple layers including the inner layer. 
     
     
       4. The coil component according to  claim 2 , wherein the sheet core has a thickness of not more than about one-third of a height of the coil component including the thickness of the sheet core. 
     
     
       5. The coil component according to  claim 2 , wherein the thickness of the sheet core is not more than about 200 μm. 
     
     
       6. The coil component according to  claim 2 , wherein the sheet core is a resin sheet containing magnetic powder. 
     
     
       7. The coil component according to  claim 2 , wherein the adhesive on the top surface of the flange portion and the adhesive on the wire are integrated. 
     
     
       8. The coil component according to  claim 7 , wherein the adhesive on the top surface of the flange portion is more extended than the adhesive on the wire in a width direction. 
     
     
       9. The coil component according to  claim 1 , wherein the wire is wound around the winding core portion in multiple layers including the inner layer. 
     
     
       10. The coil component according to  claim 1 , wherein the sheet core has a thickness of not more than about one-third of a height of the coil component including the thickness of the sheet core. 
     
     
       11. The coil component according to  claim 1 , wherein the thickness of the sheet core is not more than about 200 μm. 
     
     
       12. The coil component according to  claim 1 , wherein the sheet core is a resin sheet containing magnetic powder. 
     
     
       13. The coil component according to  claim 1 , wherein the adhesive on the top surface of the flange portion and the adhesive on the wire are integrated. 
     
     
       14. The coil component according to  claim 13 , wherein the adhesive on the top surface of the flange portion is more extended than the adhesive on the wire in a width direction.